1. Field of the Invention
This invention relates generally to dispensers, and more specifically to an apparatus for applying a flowable material to a workpiece.
2. Description of the Prior Art
Fluid containers often are fashioned from multiple parts fastened together, thereby creating joints or interfaces between mating part surfaces, such as flanges, through which fluid can migrate. In some cases the mating parts themselves can be made to effectively seal when fastened together by match-machining the parts to create conforming joint interfaces and by honing the joint interfaces to create very smooth surface finishes. A less expensive and more time efficient sealing method, however, is often desirable for those assemblies which are mass-produced.
One method for sealing production quantity assemblies employs a separate deformable gasket, typically cork, clamped between the mass-produced parts. The gasket provides an effective seal by deforming when clamped to accommodate the varying surface finishes and part-to-part variations. The addition of another part, however, presents a two-fold problem. Although inexpensive as an individual item, a separate gasket increases part count resulting in increased tracking, complexity and other inventory related costs. Furthermore, gasket failure often can be drastic, leading to gross fluid losses through the joint.
Therefore, current production sealing practices typically favor a sealing method representing a compromise between the above-described methods. Rather than using a separate gasket part, a gasket material is applied directly to the mating parts using a separate production process. Gasket materials can be applied in either a liquid or semi-liquid form onto one or both of the mating parts. The applied gasket material can also vary in form and constituency, wherein some materials dry after assembly of the mating parts while others remain semi-plastic or elastomeric. In any case, the gasket material must be deposited on at least one of the part surfaces forming the joint.
One manner of depositing gasket material in a production situation employs a hand-held dispensing gun. In more sophisticated situations a dispensing gun powered to dispense the gasket material is mounted on an articulated arm, typically the arm of a robot. The arm follows a preprogrammed path or dispensing pattern which dictates the movement of the gun relative to the surface or work path to which the gasket material is applied. Such arrangements tend to be comparatively complicated and expensive, thus leading to higher production costs. Often a cam having a pattern or profile is employed to govern the arm and gun movement, wherein the cam replaces the programming and its associated cost and complexity. Current dispensing gun and arm arrangements, however, can be limited in their range of operation due to the articulating nature of the arm. Furthermore, because the gun is often supported cantilevered from the arm, an articulated arm fully extended is susceptible to higher deflections and, therefore, potentially reduced accuracy.
A need therefore exists for an improved gasket material dispenser. Such a dispenser should have a large range of operation. Also desired is a dispenser having increased accuracy, wherein the dispenser is less prone to deflection. The dispenser should be economical both in initial cost and in recurring costs.